A model for assessing the layout structural complexity of manufacturing systems

The layout of a manufacturing facility/system not only shapes its material flow pattern and influence transportation and operation cost, but also affects logistics and parts/machine assignment decisions. The layout of manufacturing systems determines its structural complexity by virtue of its design configuration characteristics. This paper introduces a new model and indices for assessing the structural complexity of manufacturing systems layout in the physical domain. Six complexity indices, based on the physical structural characteristics of the layout, have been introduced and formulated. They are layout density, path, cycle, decision points, redundancy distribution and magnitude indices. An overall Layout Complexity Index (LCI) which combines all indices is developed using a novel method based on radar plots which is insensitive to the order of plotting the individual indices. The use of the developed LCI is demonstrated using six typical types of manufacturing systems layouts and relevant guidelines are presented. The developed model and complexity indices help design system layouts for least complexity and compare layout alternatives that meet the specifications, at early design stages. It supports making trade-off decisions regarding manufacturing systems flexibility and complexity and their associated costs.     

A knowledge-based expert system for technology acquisition in small and medium scale manufacturing organizations

Consistent and reliable decision making for technology acquisition in small and medium scale manufacturing organizations is vitally important since these firms are the backbone of national economies, both in developed and developing countries. Because of their flexibility, small and medium scale firms are successful in adopting new technologies. However, a careful analysis should be conducted in technology acquisition decisions. Since these decisions require special type of knowledge and expertise, expert system, as an important tool of computerized decision making, can overcome these multidimensional difficulties.

This paper proposes a knowledge-based approach making use of issues such as sales, processes, costs and general policies, in decision processes for technology acquisition by small and medium scale manufacturing organizations in the developing environments.     

Evaluation of flexibility for the effective change management of manufacturing organizations

In this paper, we propose selected flexibility measures which can quantify flexibility and eventually integrate it into the change management processes of manufacturing organizations, aiming to increase effectiveness and competitiveness of the European industry. These measures can be utilized either stand-alone or integrated into a change management system to influence the change direction. A classification model supporting flexibility-related aspects is also discussed. A case study presenting a recommended integration of flexibility into a change management process is described. Additionally, a service-oriented architecture on IT level that can be adopted in order to combine the flexibility calculation with the change management is presented. The final objective is to investigate the integration of quantified flexibility indicators into the change management processes of a manufacturing organization.     

Multi-objective optimization of product variety and manufacturing complexity in mixed-model assembly systems

Product variety has increased dramatically as manufacturers compete for market shares. While higher variety of products may satisfy a broader range of customers, it also introduces complexity in manufacturing. A multi-objective optimization approach is proposed to balance product variety and manufacturing complexity when designing a product family and the mixed-model assembly system. Relative complexity is introduced to measure the complexity and to find the best set of product variants to be offered while balancing market share and complexity. Numerical examples are provided to demonstrate the approach.     

ROGET: A knowledge-based system for acquiring the conceptual structure of a diagnostic expert system

This paper describes ROGET, a knowledge-based system that assists a domain expert with an important design task encountered during the early phases of expert-system construction. ROGET conducts a dialogue with the expert to acquire the expert system's conceptual structure, a representation of the kinds of domain-specific inferences that the consultant will perform and the facts that will support these inferences. ROGET guides this dialogue on the basis of a set of advice and evidence categories. These abstract categories are domain independent and can be employed to guide initial knowledge acquisition dialogues with experts for new applications. This paper discusses the nature of an expert system's conceptual structure and describes the organization and operation of the ROGET system that supports the acquisition of conceptual structures.     

Developing an expert system to assist in control system design

This paper addresses the problem of how to develop an expert system that is able to design or to assist in the design of a control system. The discussion includes how to structure the expert system, how to choose the relationship between the symbolic and numerical processor and how to divide the work among the expert system, the computer aided control systems analysis package and the design engineer. A prototype intelligent design associated is presented and an example of a compensator design is given.     

Evaluating expert system prototypes

There is a disparity between the multitude of apparently successful expert system prototypes and the scarcity of expert systems in real everyday use. Modern tools make it deceptively easy to make reasonable prototypes, but these prototypes are seldom made subject to serious evaluation. Instead the development team confronts their product with a set of cases, and the primary evaluation criterion is the percentage of correct answers: we are faced with a 95% syndrome. Other aspects related to the use of the system are almost ignored. There is still a long way to go from a promising prototype to a final system.It is maintained in the article that a useful test must be performed by future users in a situation that is as realistic as possible. If this is not done claims of usefulness cannot be justified. It is also stated that prototyping does not make traditional analysis and design obsolete, although the contents of these activities will change.In order to discuss the effects of using the systems a distinction between expert systems as media, tools and experts is proposed.     

Industrial Additive Manufacturing: A manufacturing systems perspective

As Additive Manufacturing becomes increasingly prevalent in commercial manufacturing environments, the need to effectively consider optimal strategies for management is increased. At present most research has focused on individual machines, yet there is a wealth of evidence to suggest competitive manufacturing is best managed from a systems perspective. Through 14 case studies developed with four long-established Additive Manufacturing companies this paper explores the conduct of Industrial AM in contemporary manufacturing environments. A multitude of activities, mechanisms, and controls are identified through this detailed investigation of Additive Manufacturing operations. Based on these empirical results a general four component Industrial Additive Manufacturing System is developed, together with the identification of potential strategic opportunities to enhance future manufacturing.     

Toward a cloud-based manufacturing execution system for distributed manufacturing

This paper illustrates the needs and challenges for the management of distributed manufacturing in a multi-company supply chain and processes these further as features of new IT systems. Requirements are collected from manufacturing companies and combined with insights from literature in the field of current ERP/MES system drawbacks, advantages, needs and challenges. The findings show that the needs and challenges in data integration inside SME networks are closely related to the limitations of current supply chain solutions. Current ERP-solutions lack extended enterprise support and a shared cloud-based approach. On the other hand, current MES solutions can operate the manufacturing process, but not for distributed manufacturing. As an answer to the requirements, we made a proposal for the core of architecture for next generation of MES solution in this position paper. Moreover, a pilot software tool has been developed to support the needs related to real time, cloud-based, light weight operation.     

Generative design in architecture using an expert system

The mathematician-architect Christopher Alexander has devised a theory of objective architectural design. He believes that all architectural forms can be described as interacting patterns, all possible relationships of which are governed by generative rules. These form a ‘pattern language’ capable of generating forms appropriate for a given environmental context. The complexity of interaction among these rules leads to difficulties in their representation by conventional methods. This paper presents a Prolog-based expert system which implements Alexander's design methodology to produce perspective views of partially and fully differentiated 3-dimensional architectural forms.     

A holonic approach to dynamic manufacturing scheduling

Manufacturing scheduling is a complex combinatorial problem, particularly in distributed and dynamic environments. This paper presents a holonic approach to manufacturing scheduling, where the scheduling functions are distributed by several entities, combining their calculation power and local optimization capability. In this scheduling and control approach, the objective is to achieve fast and dynamic re-scheduling using a scheduling mechanism that evolves dynamically to combine centralized and distributed strategies, improving its responsiveness to emergence, instead of the complex and optimized scheduling algorithms found in traditional approaches.     

L-CATA: A logic-based expert travel system

L-CATA (Logic-based Computer Aided Travel Assistant) is a logic-based expert database system, which asks the user to input his query specification, such as starting place, destination, constraints, rules and goals, etc., and outputs a list of flights meeting the traveller's specification; together with an alternative list which may not quite meet the user's specification but optimizes his goals. L-CATA is written as a deductive database system, and uses heuristic rules to prune its search of the database. Unlike other air-travel related expert systems, L-CATA does not attempt to model the traveller. Instead, L-CATA complements existing Computer Reservation Systems by providing comprehensive individually tailored advice and information to the traveller. There are several approaches to implement such a system. The logic approach is a very promising one, and the aims of L-CATA can be more easily achieved by using it. In this paper, we present a logic approach to the L-CATA expert database system, and provide a theoretical foundation for such a database system.     

An expert system approach for die and mold making operations

In the modern manufacturing of sophisticated parts with 3D sculptured surfaces, die and mold making operations are the most widely used machining processes to remove unwanted material. To manufacture a die or a mold, many different cutting tools are involved, from deep hole drills to the smallest ball nose end mills. Since the specification of each tool is very different from each other, each mold or die is specific with their complicated shapes and many machining rules exist to consider, a great deal of expertise is needed in planning the machining operations. An expert system (DieEX) developed for this purpose is described in the present work. The geometry and the material of the workpiece, tool material, tool condition and operation type are considered as input values and various recommendations about the tool type, tool specifications, work holding method, type of milling operation, direction of feed and offset values are provided.     

A multilevel multilayer framework for manufacturing control

As a contribution to the debate on CAPM reference models derived from control theory concepts, we formulate the basic computer-aided production management problem from a control theoretic point of view and examine the main difficulties in using this crude framework as a basis for decision-making. Next, different hierarchical approaches are shown to be potentially of value in overcoming the two main difficulties highlighted by the control theoretic paradigm, i.e. dimensionality and the discrete event nature of manufacturing systems. In this context, we examine the literature concerned with both multilevel control as well as multilayer control where the notion of aggregation plays a key role. Next, a mixture of multilevel and multilayer control is used to provide a framework for production planning and scheduling for multiline batch manufacture with application to detergents plants. This framework would appear to be of values also in discrete parts manufacture and this is also highlighted.     

Report to the Alvey Directorate on a short survey of expert systems in UK business*

Simpler expert systems are practical and being implemented now by self-taught teams, with little risk at relatively low-cost, to produce modest but unusual gains. It is necessary to correct the impression, much heralded hitherto, that expert systems are inherently complex, risky and demanding. This impression is a handicap to competitive developments in the supply and usage of advanced information technology.     

Intelligent knowledge based expert inventory control system for computer integrated manufacturing

The paper discusses the framework and development of an expert inventory management system for integrative manufacturing planning. The system developed with an artificial intelligent language provides a linkage between management and computer-integrated manufacturing(CIM), has the following major elements: data base to represent a hierarchical tree using recursive objects on different levels; knowledge base containing heuristic rules; goal oriented interaction; and backtracking interface procedures. Potential benefits of the system includes: better manufacturing planning, reduced inventory levels and production lead times, and consistent inventory control records.     

From decision tables to expert system shells

Building and maintaining high quality knowledge based systems is not a trivial task. Decision tables have sometimes been recommended in this process, mainly in verification and validation. In this paper, however, it is shown how decision tables can also be used to generate, and not just to validate, knowledge bases and how the transformation process from decision tables to knowledge bases can be organized. Several options to generate rules or other knowledge representation from decision tables are described and evauluated.

The proposed generation strategy enables the knowledge engineer to concentrate on the acquisition and modelling issues and allows him to isolate the knowledge body from its implementation. The generation process has been implemented for two commercial tools, AionDS and KBMS and has been applied to real world applications.     

Xrays: A fuzzy expert system for qualitative XRD analysis

This paper describes the development of a fuzzy expert system termed XRAYS for identification of minerals via X-ray diffractograms. The system emulates the well-known (manual) Hanawalt method, thus avoiding the black-box approach of most computer search/match programs. The mineral subfile of the JCPDS Powder Diffraction file is stored in a database, from which the Hanawalt groups are created by the program. The expert system then carries out “manual” search following the steps prescribed for the Hanawalt method. Fuzzy comparisons and fuzzy arithmetic operations are employed in searching for matches. A list of candidate minerals is output in decreasing order of confidence. Graphical comparisons between the unknown pattern and candidate patterns are displayed on the screen to allow the diffractionists to make visual comparison as to the degree of match. Several examples containing from two to six minerals are used for illustration.     

An introduction to expert systems

The paper considers the features of expert systems which make them of educational interest, and discusses issues of knowledge representation through rule sets, and how such systems can be used to give explanation and advice. Working systems are outlined in Medicine, Geology and Computing. Some limitations of expert systems are noted and their future potential assessed.